Effect of Alloying Elements and Processing Parameters on Mechanical Properties of Austempered Ductile Iron

Abstract

In the present work, austempering is carried out for three different grades (Unalloyed, copper alloyed and Nickel alloyed) of ductile iron. After that the variation of mechanical properties (Hardness, Tensile strength and Elongation) and microstructure of the austempered ductile iron (ADI) with alloying elements (Copper and Nickel) and austempering process variables (austempering temperature and austempering time) were studied. It is found that, with increasing austempering time hardness, tensile strength and elongation are increasing but with increasing austempering temperature hardness and tensile strength are decreasing and elongation increasing. Austempered ductile iron with alloying element (Cu or Ni) is showing some improved mechanical properties such that: higher strength, hardness and lower elongation, than the unalloyed austempered ductile iron. In Microstructure, higher ferrite fraction is observed for higher austempering time and higher austenite fraction is observed for higher austempering temperature, for all the three grades of austempered ductile iron.